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Drive letter changed - how to change back?

Last Modified: 2012-05-06
Hi EE,

One of my external drives was designated "M" drive. After plugging in a flash drive and removing it; I noticed the drive letter had changed from "M" to "H." How do I change it back to M?

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Lee W, MVPTechnology and Business Process Advisor
Most Valuable Expert 2013

Do to the Computer Management Administrative Tool.  Navigate to the Storage section and then Disk Management.  Locate the drive and right click it - then select "Change Drive Letter and Paths..." option.  (If the drive is in use, including simply being open, it may require a restart to take effect).



Quickest, best answer ever received! I had more trouble just finding the darn Computer Management Administrative Tool, since it wasn't listed under anything in the Control Panel. I only found it by clicking a link from the Help function.

Do you know how I can get it back under CP?

thanks again.

Control Panel/Administrative Tools/Computer Management/Disk Management.
Lee W, MVPTechnology and Business Process Advisor
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WOW. Great suggestions!

akahan, I'm including a screen shot of my results after going to Control Panel > Administrative Tools because I'm not seeing anything like you're suggesting should be there. Please advise.
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Control panel disk manager


I'm feeling real stupid here. First, I do have the regular OS for XP SP2 (came installed with Dell PC). I've searched for 30 minutes, and on my Control Panel, can't find "Disk Manager."  Where should it be located? Thanks for your help.
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it is called System
also accessed from start>Rightclick My computer>properties

Go to your start menue look on the right under network places if you have that listed
or open my computer on the left side>> System tasks below that
Other places
I'm on my laptop now but it should look the same,

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Hi photoman.

Your question has been pretty well answered by the comments above.  I had typed out some information earlier before being woken up and asked to go and deal with some issues at work, but I'm going to post it now as ADDITIONAL information that may be useful or helpful to you in the future.

Can I ask a pretty cheeky question.  Why is it so important to have your external drive assigned to "M:"?

Perhaps you have a load of batch files that run backups or file synchronisation, and expect the drive to be at M, or (looking at the "Titan Backup" shortcuts in your "Administrative Tools" folder) installed backup software that needs the drive to be M.  If that's the case, then I can see logic there, and I don't want to push my opinions too much on you, but ... ;-)

In general it makes more sense to have your Drive letters following in order like this:
Hard Drive 1 (System Drive on Primary Master channel) = C
Hard Drive 2 (2nd hard drive on Primary Slave channel) = D
CD-Rom/DVD-Rom (on Secondary Master channel) = E
CD-RW/DVD-RW (on Secondary Slave channel) = F
External USB Hard Drive = G
Flash Drives = H, I, J, etc.

SATA connections may be different.  The above is based on older IDE (or PATA) connections with wide ribbon cables where IDE Channel assignment is dictated by pin jumpering on the back of each drive and/or whether the drive is on the Middle or End connector of the cable (as with Cable Select jumpering or "CSL").  In general, the drives A to F would be assigned the above Drive Letters (as explained by Merete in the comment immediately above).

If you only have and use one external USB Hard Drive, it makes sense to assign it as G in Disk Management while you have it connected, so that it will (or at least should) be assigned that letter every time you connect it.  It's probable that you have that external drive connected more regularly than Flash Drives, cameras, etc, so it's less likely to be reassigned to another drive letter there.

Because "Mass Storage" devices like USB Flash Drives, Digital Cameras, MP3 Players, etc will take the next available Drive Letter each time they are connected, when you connect just one of those devices at any one time it will be assigned the next letter H.  So your Flash Drive could be H one minute, then when disconnected it, your Digital Camera would then be H when connected.  Connect two or more at once, and they would be assigned H, I, J, etc, as you connect them.  There's usually no pressing need to have a static drive letter for that type of portable medium anyway.

I suppose you'll be thinking "OK, but if I make my external USB Hard Drive take the letter M, then I would have to connect 6 Mass Storage devices simultaneously before the letters G to L were taken and the letters then had to jump to N past the USB Hard Drive if I connected a 7th Mass Storage Device."

Well, I suppose that is pretty unlikely, and who is to say that your logic is any worse or better than mine, but I just like to have things running sequentially.  Where it DOES (or would) make a difference would be if you had two large hard drives divided into a few logical drives or partitions on each.  For example, your main system drive could have 2 partitions (C and D), and your big slave drive used for data storage could have 3 partitions (E, F, and G).  Your CD/DVD-Rom and CD/DVD-RW drives would usually come next as H and I.  That's already 7 Drive Letters taken up before you get to external USB Drives (or more correctly the letter that would be assigned to one when connected).

Maybe this DOES reflect your current drive configuration and your external USB Hard Drive has been slotted in BEFORE the CD Drives as H, resulting in them being bumped up to I and J respectively.  That would make a difference and could be a nuisance if it came to you doing a repair install on a program or driver installation, where the registry tells it to look for the setup CD at the same drive letter as it was during the original setup and you then have to tell it otherwise.

My preference has always been to have the permanently connected internal drives assigned sequential drive letters in the order I mentioned above, ie. System Drive, Slave storage drive, CD/DVD-Rom, CD/DVD-RW, and THEN my external USB Hard Drive.  Thereafter the drive letters can be dynamically assigned as and when I connect and Safely Disconnect Flash Drives, camera, etc.  You CAN shuffle the drive letters for "fixed" (internal) drive types around, but it can lead to confusion, so you are better leaving them as they are.

One reason for my preference is based on the fact that I deliberately configure my external usb hard drive as "optimized for quick removal" so that it "Safely Disconnects" when switched off with less potential for data loss, rather than would be the case if set for "performance".  I have consistently done this, so I am not sure if the "for performance" setting would have any effect on drive lettering, like grouping it after fixed drives, but it may be something you would wish to look at under the Drive's (Right-Click > ) "Properties".

The other reason is purely a visual and usability one.  My external usb hard drive is used for data storage, and as such I am always dragging and dropping, copying and moving, to and from that drive.  I like it to be right up there in the left folder tree of Windows Explorer with the other fixed drives without having to keep scrolling down past Flash Drive letters in between the fixed drives' letters and the external one.

It's like everything else in life though.  Every computer user has their own preferences, whether they have been thought out logically or are just something they have become accustomed to because that's how it happened to be configured to begin with.  It would be so much easier and quicker to fix other peoples' computers if everything was in a standard place and was where I expected it to be rather than having to hunt through the start menu for a shortcut, or wonder why Control Panel or My Computer wasn't displaying the items I wanted to lay my hands on quickly.  I often forget to reset Folder Options and leave someone with confusing file extensions or mysterious hidden files and folders they have never seen before ;-)

All you have to do is look at Merete's apparent preference for showing Folder Tasks as the left pane and "tiles" as opposed to the way you (and I) prefer the Details view, although I like to see my folder tree at the left.  It looks like you got there by double-clicking My Computer, then Control Panel, then Administrative Tools, whereas I have my Control Panel as a popout Menu from Start > Settings, and any "sub-folder" thereof will be a popout menu also.  That option is available if you Right-Click the Start button, choose Properties, then click the "Customize" button against "Start menu" or "Classic Start Menu" (depending which one you prefer and are using).  Look for the "Expand ..." options.

If, like me, you often need to check Disk Management, Services, Event Viewer, etc, then it would be a good idea while customizing the Start Menu to tick the "Display Administrative Tools" and "Expand Control Panel" boxes.  Either that, or create a new folder right at the top of your Start Menu > Programs with new shortcuts (or copies from elsewhere on the Start Menu) to your commonly accessed tools like:
%SystemRoot%\system32\compmgmt.msc /s
%SystemRoot%\system32\services.msc /s

I'm not sure if you are aware, but Control Panel Applets are (mostly) *.cpl files.  These are very much like DLL files in that they contain resources including the Dialog tabs you are used to seeing.  You can create a shortcut that has the command to open specific dialog tabs from within a named *.cpl file.  This is handy to know, because items in the Control Panel aren't standard shortcuts that can be Right-Clicked on to get the shortcut properties to use elsewhere.  For example, say I want a quick access shortcut to "Internet Options > Advanced tab".  A quick search in Regedit (or just checking the properties of files found by searching for files named *.cpl), tells me that the file containing the resource is:

The command used by Windows to open a Control Panel Applet is:
In full:
%systemroot%\system32\RunDLL32.exe shell32,Control_RunDLL %systemroot%\system32\filename.cpl

RunDLL32.exe shell32.dll,Control_RunDLL filename.cpl

Abbreviated even more but still functional:
rundll32 shell32, Control_RunDLL filename.cpl

or (in windows XP using the handy %systemroot%\system32\control.exe):
Control filename.cpl

With most Control Panel Applet files, if you add a comma or double-comma after the *.cpl extension in the command and then add a number that corresponds with the number of the dialog tab, it will open to that.

So, a shortcut to Internet Options > "Advanced" tab (the 6th tab from the left where the first one is Zero) is:

In Full:
%systemroot%\system32\RunDLL32.exe shell32.dll,Control_RunDLL %systemroot%\system32\inetcpl.cpl,,6

rundll32 shell32,Control_RunDLL inetcpl.cpl,,6

control inetcpl.cpl,,6

Hopefully you will find this information interesting/useful/helpful, but PLEASE DO NOT include me in the points.  As I said, your question has been more than adequately answered by earlier contributors and this is just an addendum or appendix.


Whoops, I left a space where it shouldn't have been here:

"Abbreviated even more but still functional:
rundll32 shell32, Control_RunDLL filename.cpl"

This should read:
rundll32 shell32,Control_RunDLL filename.cpl


The only way I could locate it was by going to Run > compmgmt.msc. I've included shots of that + the My Computer > rt click > properties (and cannot find anything with "System").

I have numerous shortcuts set up that follow the drive paths to open docs and applications. when the drive letter changes, none of the shortcuts work. that's the reason I want to lock down the letters.

Is it fair to assume that the only way to create permanent drive letters is by trying nobus's suggestion http://www.uwe-sieber.de/usbdlm_e.html ?

Thanks to all.
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A few comments:

 First of all, the only shortcuts I have point to the LaCie 750GB external Drive, my internal C drive, and my internal D drive. There is no "H" drive that I am aware of.

The other thing is you mentioned about system restore monitoring my removable drives. I don't remember ever setting anything up specifically to do this. Honestly, I don't even know what it means. Is there a better approach that you would recommend, that would not take a huge amount of work or technical expertise?

Bill, thanks again for your help.

Yes, "System Restore".  Well, it's a strange beast really, works to fix some problems, but useless for others.

This feature was first made available to "home users" in Windows ME.  Like Windows ME, this feature was very good as a concept, but not terribly good in final execution.  It was rushed through to get on the "millenium" bandwagon and was left half-baked.  The idea behind it was that if your system did not start up, or if you installed a driver or software that screwed things up, you could dial it backwards in time to the state it was at before the last "Restore Point" was created.

The feature uses a specified % of your hard drive to take a "system snapshot" of your computer and back up a range of files and settings to hidden folders.  You can create a restore point manually, and in many cases a large software installation like MS Office, or some Windows Updates, usually create a new restore point automatically before installing.  If things go wrong, then you can restore it back to the previous state using the Windows program interface or from the command line in extreme circumstances.  The space assigned for the restore points works as a last-in first-out, where new restore points push out the oldest.

In Windows XP, System Restore runs as a background "Service" named "srservice".
Right-Click on My Computer > Manage > expand "Services and Applications" > click on "Services
type the command   services.msc /s    into the Start Menu's Run field.

It doesn't actually hog too much in the way of resources, and having it monitor your system hard drive is usually a good idea if it gives you one option of undoing bad changes.  It should never be relied upon as an alternative to having a proper backup strategy for catastrophes though.  Professionals or individuals with a lot of data to lose tend to use Disk Imaging  programs that mirror the hard drive to another drive, eg. DriveImage, Acronis TrueImage, and a number of other equally popular programs.

The thing about System Restore is that it does not back up your data.  It is only intended to get Windows back up and running, or running without conflicts that keep crashing it, and to achieve this it is limited in what files and settings it backs up.  Because of this, having it monitoring any hard drive other than the drive on which Windows is installed is really a waste of time and hard drive space.  Over and above this, if an external USB hard drive is being monitored in this way, then it isn't really optimised for quick removal such as switching off the drive without the potential for data loss.

The annoying thing is that System Restore will automatically begin monitoring new external hard drives connected to the system without telling you.  A lot of the time if you disable System Restore monitoring for that drive, if you later disconnect it and re-connect it, Windows re-enables it for monitoring again.

I'll paste some links for you that will be handy references and explain its usage in more detail, but I'll just tell you how to turn off system restore monitoring of your external usb hard drive.  Refer to your previously attached screenshot:
and get back to that dialog tab again.
Click on the External USB Drive to select it, then click the "Settings" button.  You will see a "Turn off system restore on this drive" check box.  If you check that and click the OK button, it will take you back to the list of drives and show that drive as "Turned Off".  Click the "Apply" button of the System Properties dialog if it becomes available, and cclick OK to close it.

If your Folder Options > View settings allow you to see hidden and system folders and files, then you may already have been aware of a folder named "System Volume Information" in any hard drive that was being monitored by System Restore.  While a drive is being monitored, you will always be refused access to that folder in Windows Explorer, but once you disable System Restore on that drive, the folder can be accessed and deleted quite safely.  It normally prompts you whether to allow deletion of an *.ini file that is in a sub-folder, but you can say yes to that.

That's a little less clutter on the drive and one less super-hidden and protected data on a drive that you are using to store your own data.  Perfectly OK for the system drive containing the Windows installation, but useless for a storage drive.  You'll see why this is the case in one of my linked pages below that tells you what System Restore CAN restore and what it CAN'T.

Before I paste the links, I think that in the end your "problem" with the drive letters is really just one of those annoyances in Windows that we have to live with from time to time.  It's easy to forget how much harder life was in Windows versions prior to XP when connecting and disconnecting USB devices like Flash Drives, digital cameras, External Drives, MP3 Players, etc.  My opinion is that if we have to live with annoyances like drive letter changes, then the benefits far outweigh them.

I have experimented with attempting to "batch modify" Windows shortcuts to change their target paths, but gave up in the end because the contents are not standard editable text.  I suppose there are probably utilities or Visual Basic Scripts that allow you to do this for selected shortcuts (I have probably downloaded some in the past), but I have never used any.  I do recall one of the experts here providing me with a *.vbs script that listed all the target paths of shortcuts on my start menu, and there are also cleanup utilities that check the paths and report broken links (Win98se CD had \tools\reskit\desktop\chklnks.exe), and it's possible that the WinXP Support Tools have something similar.

On hard drives formatted as NTFS, there can exist two different types of "links".  Hard Links and Symbolic (or Soft) links.  Windows Shortcuts are Symbolic links and just store the path of the target in them, so if the target moves then the link breaks.

Hard Links are a special type of link (or more correctly a file) that have the "target" stored in the filing system of the hard drive and will always track the target even if it moves.  Unbreakable links so to speak.  It's very technical and not really something to be messed with though, even though utility programs exist to create hard links quite easily (eg. Windows XP program FSUTIL.EXE).

Creating a new Windows Shortcut, however, is pretty straightforward from the command line.  You could probably use an older SHORTCUT.EXE from the support tools of previous Windows versions, or a fairly simple *.vbs file courtesy of http://www.ss64.com/nt/shortcut.html

I do believe that the utility suggested by nobus way back in the question (http://www.uwe-sieber.de/usbdlm_e.html) is probably your best option for managing the problem.

OK, here's the links about System Restore that you can copy and paste out to file as a future reference.


Use System Restore to Undo Changes if Problems Occur:

Windows XP System Restore Is Easy to Use:

How to use system restore in windows xp:

About Windows XP System Restore:

Windows XP System Restore FAQ:

Troubleshooting steps for issues when you try to use the System Restore tool in Windows XP:

How to start the System Restore tool by using the safe mode option with the Command prompt in Windows XP:

Disabling or enabling Windows XP System Restore when infected by a virus, to prevent reinfection:

What is not restored when performing a System Restore?:

Can I use System Restore in place of Windows Backup Utility?:

Using the "Automated System Recovery" (ASR) to create and recover a backup using Microsoft's Windows XP Backup Utility:


WOW. And I thought this was a no-brainer. Thanks for your extended and very complete answer!


thanks for all your help.

You're welcome.  It was just some additional information that I know isn't really directly related to the question, but no harm in sharing.

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